It’s been nearly five years since Emma Watson last appeared as Hermione Granger in the Harry Potter series, and the 25-year-old actress continues move far beyond the magical adventures of her childhood. In her new movie Colonia, Watson plays Lena, a young woman desperate to find her missing boyfriend Daniel (Daniel Brühl) amid the political tumult of early 1970s Chile. (Watch the exclusive first trailer above.) Following his trail to a secretive, isolated enclave called Colonia Dignidad, Lena herself becomes trapped inside the dangerous and brutal cult that fronts as a charitable mission run by a man named Paul Schäfer (Michael Nyqvist). As Schäfer says ominously in the trailer, “Once you join us, you must remain.”

Based loosely on true events, the film takes place just after the violent 1973 military coup that put General Augusto Pinochet into power in Chile. A real-life settlement, Colonia Dignidad was an ominous, pseudo-religious community that was later revealed to have Nazi ties, to employ torture, and to engage in an array of other criminal activities, including child abuse.

Directed by Florian Gallenberger, who won an Oscar in 2001 for his live-action short film Quiero Ser (I Want to Be…), Colonia enters select theaters on April 15.